This invention is concerned with a mould opening and closing mechanism for a glassware forming machine operable to move opposed mould portions between a mould-closed position, in which the opposed mould portions engage one another and co-operate in defining a mould cavity, and a mould-open position in which the opposed mould portions are separated from one another.
In a glassware forming machine of the so-called "individual section" type, a plurality of sections, each of which is an individual glassware forming unit, are arranged side by side to receive gobs of molten glass from a common source in a predetermined sequence. Each section comprises a blank mould station at which gobs of molten glass are moulded into parisons by either a blowing or a pressing operation, a parison-transferring mechanism operable to transfer parisons from the blank station to a blow station of the machine, and a blow station at which parisons transferred to the blow station are blown into articles of glassware. The blank station and the blow station of each section each have a mould opening and closing mechanism operable to move opposed mould portions between a mould-closed position and a mould-open position. At the blank station of a section, the mould portions co-operate in defining a mould cavity in which a gob can be moulded into a parison and, at the blow station of a section, the mould portions co-operate in defining a mould cavity in which a parison can be blown into an article of glassware. Where the section receives only one gob at a time, the mould opening and closing mechanisms are arranged to move the portions of only one mould, but where the section receives more than one gob at a time, the mechanisms are arranged to move the portions of a like number of moulds simultaneously.
In a conventional glassware forming machine of the individual section type, the mould opening and closing mechanisms at the blank station and the blow station are similar in construction. Each such mechanism comprises two mould support arrangements, each mould support arrangement comprising a supporting arm mounted for movement about a first vertical axis defined by a pivot pin mounted so that the axis remains stationary, the first axes of the supporting arms being coincident and defined by a single pivot pin. Each mould support arrangement also comprises a mould portion support mounted on the supporting arm for pivoting movement about a second vertical axis which moves with the supporting arm. The mould portion supports are only able to make limited pivoting movement about the second vertical axis, being restrained by a pin of the supporting arm which enters a hole in the mould portion support, this pivoting movement being provided to equalise the pressure across the face on which the mould portions engage one another in the mould-closed position. The mould portion supports are arranged to support one or more mould portions, depending on the number of gobs supplied to the section at a time, so that opposed mould portions can be supported one on each mould portion support. The mechanism also comprises drive means operable to pivot the supporting arms of the support arrangements to move the mould portions supported by the mould portion supports between their mould-open and mould-closed positions. Thus, one of the supporting arms is pivoted clockwise about the first vertical axis while the other supporting arm is pivoted anti-clockwise about the aforesaid first vertical axis. In a conventional machine, the drive means comprises motor means operable to turn two vertical shafts about longitudinal axis thereof, one clockwise and the other anti-clockwise, through a predetermined angle. Two arms are fixed to and project horizontally from the vertical shafts, one from each shaft, and two links pivotally connect the arms to the supporting arms of the mould support arrangement so that, when the shafts are turned, the supporting arms pivot about their first vertical axes, one clockwise and the other anti-clockwise.
Although, in a conventional mould opening and closing mechanism as described above, the mould portion supports are mounted in a simple manner on arcuately moving supporting arms, the mechanism suffers from the disadvantages that, where more than one mould portion is supported on each mould portion support, the distance moved by the mould portions is not equal since the distance moved depends on the distance from the first vertical axis. Since space is very much at a premium in an individual section type machine, this is a serious disadvantage where a number of mould portions are mounted on the same mould portion support. Furthermore, the mould supporting arms are swung through a relatively large angle, typically 65.degree., so that the time taken to open and close the moulds is longer than is desirable. While alternative mould opening and closing mechanisms have been devised in which the mould portions are moved linearly towards or away from one another, these mechanisms have involved replacement of the simple mounting of the mould portion support on an arcuately moving arm and the introduction of more complex arrangements.
It is an object of the present invention to provide a mould opening and closing mechanism in which the aforementioned disadvantages are avoided without replacement of the mounting of the mould portion supports on arcuately moving supporting arms.